A virtual host is an alternative name, registered in DNS, for an IP address. Virtual hosting takes one of two forms:

Multiple names can resolve to a single IP address.

Multi-homed hosts, that is machines with more than one network interface, can have a different name for each IP address.

Jetty users often want to configure their web applications taking into account these different virtual hosts. Frequently, a machine with a single IP address has different DNS resolvable names associated with it, and a webapp deployed on it must be reachable from all of the alternative names. Another possibility is to serve different web applications from different virtual hosts.

You can set virtual hosts in several different ways, including:

Using a context XML file in the context directory: setVirtualHosts. This is the preferred method.

Within an explicitly deployed webapp (no webapp provider) listed in jetty.xml or similar.

Using a WEB-INF/jetty-web.xml file (deprecated, but works with the webapp provider if you do not use the context provider).

For descriptions of the various ways to configure Jetty, including links to documents that provide detailed configuration instructions, see How to Configure Jetty.

The examples that follow set virtual hosts in the preferred way, by calling the method ContextHandler.setVirtualHosts.

Configuring Virtual Hosts

When configuring a web application, you can supply a list of IP addresses and names at which the web application is reachable. Suppose you have a machine with these IP addresses and DNS resolvable names:

333.444.555.666

127.0.0.1

www.blah.com

www.blah.net

www.blah.org

Suppose you have a webapp, xxx.war, that you want all of the above names and addresses to serve. You would configure the webapp as follows:

Assuming you have configured a connector listening on port 8080, webapp xxx.war is available at all of the following addresses:

http://333.444.555.666:8080/xxx

http://127.0.0.1:8080/xxx

http://www.blah.com:8080/xxx

http://www.blah.net:8080/xxx

http://www.blah.org:8080/xxx

Configuring Different Webapps for Different Virtual Hosts

You can configure different webapps for different virtual hosts by supplying a different list of virtual hosts for each webapp. For example, suppose your imaginary machine has these DNS names and IP addresses:

333.444.555.666

127.0.0.1

www.blah.com

www.blah.net

www.blah.org

777.888.888.111

www.other.com

www.other.net

www.other.org

Suppose also you have another webapp, zzz.war. We want xxx.war to be deployed as above, and zzz.war to be deployed only from 777.888.888.111, www.other.com, www.other.net and www.other.org:

Configuring Different Webapps for Different Virtual Hosts, But at the Same Context Path

In the example above, webapp zzz.war is available not only at a certain set of virtual hosts, but also at the context path /zzz, whilst the other webapp is available at both a different set of virtual hosts, and at a different context path. What happens if you want them at the same context path, but still at different sets of virtual hosts? You just supply the same context path for each webapp, leaving the disjoint set of virtual host definitions as before:

Configuring Virtual Hosts with Non-ascii Characters

International domain names are names containing non-ascii characters. For example "http://www.bücher.com". The DNS internally remains based on ascii, so these kinds of names are translated via an encoding called punycode into an ascii representation. Modern browsers detect these non-ascii characters in URLs and automatically apply the punycode encoding. For example, typing this URL into a browser:

http://www.åäö.com:8080/test/

is translated to the following url:

http://www.xn--4cab6c.com:8080/test/

To use internationalized domain names with Jetty virtual hosts you need to supply the punycode form of the name in your context xml file (and of course you need to supply it to your DNS setup).

For example, if you are running a webapp on port 8080 at context /test, and you want to configure a virtual host for www.åäö.com, you configure its ascii equivalent in the context xml file for the context:

After starting Jetty, you can enter the url http://www.åäö.com:8080/test/ in a browser and reach the webapp.

If you don't have any webapps deployed at /, hitting the URL http://www.åäö.com:8080reaches Jetty's default handler, which serves back a 404 page listing the available contexts:

Error 404 - Not Found
No context on this server matched or handled this request.
Contexts known to this server are:
/test@ www.xn--4cab6c.com:8080 ---> WebAppContext@82d210@82d210/test,file:/tmp/Jetty_0_0_0_0_8080_test.war__test_www.xn..4cab6c.com_1jadjg/webapp/,/home/janb/src/jetty-eclipse/jetty/trunk/jetty-distribution/target/distribution/webapps/test.war

Notice that the link already has the punycode transformed domain name in it.